Authors:
Vladimir Estivill-Castro
and
René Hexel
Affiliation:
School of ICT, Griffith University, Nathan Campus, Nathan 4111 and Australia
Keyword(s):
Executable UML, UML State Charts, Model-based Testing and Validation, Modelling Behaviour.
Related
Ontology
Subjects/Areas/Topics:
Applications and Software Development
;
Executable UML
;
General-Purpose Modeling Languages and Standards
;
Languages, Tools and Architectures
;
Model Execution and Simulation
;
Model-Driven Software Development
;
Models
;
Paradigm Trends
;
Software Engineering
Abstract:
For the UML, state charts are by far the most used modelling tools, both to communicate behaviour and to produce executable models. We investigate the inherent asymmetry of On-Entry and On-Exit Actions in UML Statecharts. We show first that the apparently simple and symmetric rules for handling the sequencing of On-Entry and On-Exit actions are hard to fully comprehend and apply effectively by software developers. Second, defining a semantics that results in executable models for applications such as reactive-systems and real-time systems is very delicate. Third, formal verification can be hampered because the semantics results in a combinatorial explosion of states. We evaluate the understandability of the semantics by taking out experiments with various tasks comprising sample UML Statechart and logic-labelled finite state machines (LLFSMs). Several experiments with software developers enable us to dissect how issues of understandability of state diagrams relate to nesting or event
-driven vs logic-labelled. Since logic-labelled finite state machines achieve model composition through a subsumption architecture (suspend/restart/resume) we propose a specific alternative semantics for logic-labelled finite state machines that is suitable for robotic and embedded systems.
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